A Case of Bilateral Endobronchial Squamous Cell Carcinoma Mimicking Asthma

Partial or complete obstruction of bronchial tree by endobronchial tumours results in obstructive hyperinflation, non – resolving pneumonia, or atelectasis. Partial endobronchial obstruction may be associated with wheezes, which mimic asthmatic attack, non – responding to inhaled medications. Here, we report a rare case of bilateral endobronchial squamous cell carcinoma, presenting with obstructive hyperinflation and wheezes, which was wrongly diagnosed as ‘difficult asthma’ in a forty – year old male. Histopathology of endobronchial biopsy tissue ultimately revealed the

suggestive of atopy, childhood asthma, and GERD.However, the patient was diagnosed as having 'difficult asthma' and advised for inhaled long acting β 2 agonist and inhaled corticosteroid combination and short acting β 2 agonist.Due to lack of symptomatic improvement, at first montelukast, and then sustained -release theophylline were added, but again, no improvement was documented.Different antibiotics are also advised to treat 'exacerbations'.In this stage, he attended our hospital with same symptoms with increased severity.
On general survey, there was anemia, but no clubbing, cyanosis and lymphadenopathy.His temperature was 97 0 F, pulse -110 bpm, respiratory rate 24 breaths/minute and BP -110/70 mmHg.He was comfortable on sitting upright position.On examination of respiratory system, there was tachypnoea, intercostal suction and over activity of accessory muscles of respiration.Mediastinum was central.Hyperresonant percussion note was found over second, third and fourth intercostal spaces along left midclavicular line, fourth and fifth intercostal spaces along left midaxilary line and left interscapular area with diminished vesicular breath sound over same areas.Fixed, monophonic, localizedwheezes were audible over right and left infraclavicular areas.
Complete hemogram and blood biochemistry were normal, except increased eosinophil count (720/ cmm).Sputum for AFB was negative.Chest X-ray and electrocardiogram were normal.Spirometry showed obstructive pattern without reversibility with short acting β 2 agonist inhalation.Contrast enhanced CT scan of chest revealed left upper lobe hypertranslucency and intraluminal lesion in right and left main bronchi (Figure -1).Fiberoptic bronchoscopy revealed J MEDICINE 2014; 15 : 61-63 .widened carina, infiltrated with whitish nodules; a proliferative, nodular growth partially occluding the lumen of left main bronchus and multiple nodules involving right main bronchus, infiltrating distally and partially occluding the opening of right upper lobebronchus (Fig. -2).Endobronchial biopsy was taken from the nodules of both sides and histopathological examination revealed squamous cell carcinoma (Fig. -3).Post -bronchoscopy sputum for malignant cells was negative.USG of whole abdomen, colonoscopy and upper GI endoscopy were within normal limit.Radionuclide bone scan, contrast enhanced CT scan of brain, and whole body CT scan were normal.Hence bilateral endobronchial squamous cell carcinoma was diagnosed, and the patient was advised cytotoxic chemotherapy, but he was lost to follow up.

Discussion:
[3][4][5][6][7] Lung cancer is most common malignancy throughout the world and more than 50% of these tumours involve central airways. 8Among centrally placed lung cancers, squamous cell and small cell histopathological subtypes are most common, especially in tobacco smokers.Airway involvement may be due to bulky endobronchial disease, endobronchial extension, or external compression of the airways by tumour itself or by lymphadenopathy. 9  Endobronchialtumour may obstruct central airways partially or completely.Complete obstruction of larger airwaycauses absorption collapse or atelectasis which is easily diagnosed by radiology and bronchoscopic biopsyoften reveals its histopathological diagnosis.
On the other hand, partial obstruction of airway by endobronchial neoplasm may result in recurrent postobstructive pneumonias, or air trapping in the segments distal to the obstruction.Non -resolving pneumonia may be absent as draining of secretions from distal segment is often adequate due to follicular nature of the endobronchial growth, causing incomplete obstruction.But this type of growth may act as 'ball -valve' and air trapping during expiratory phase results in obstructive hyperinflation.
However the patient may also present withdyspnoea, cough, and focal, fixed, monophonic, inspiratory wheezes with absolutely normal chest X-ray.This may simulate obstructive airway disease, especially asthma in young age group, but treatment with inhaled corticosteroid and inhaled long acting b 2 agonist does not result in any improvement.On contrast enhanced CT scan of thorax, endobronchial follicular lesion is often missed.Hence fiberoptic bronchoscopy is essential in these cases of 'difficult asthma' for early diagnosis of endobronchial malignancy and early surgical intervention may change the future prognosis.

Conclusion:
Fixed monophonic wheeze is a characteristic sign of incomplete occlusion of a main stem or lobar bronchus by tumours, foreign body, cicatricial stenosis, or intrabronchial granulomata.The source of wheeze is a jet of air flowing at a high velocity through a narrow chink which sets the endobronchial mass and the adjoining walls of the bronchus into rapid oscillation.This wheeze may be inspiratory, expiratory, or both.The wheeze may disappear when the patient lies down from one side to the other.This is an important sign of obstructive endobronchial lesions.